Effects of oral immunonutrition on histological changes of inflammatory infiltration of the tumor microenvironment among patients with a new diagnosis of gastric cancer

Objectives: We assessed the effects of oral immunonutrition (OI) on the inflammatory infiltration of the tumor microenvironment (TME) of patients undergoing surgery for gastric cancer. Methods: We analyzed patients at the time of their first gastric cancer diagnosis. We collected surgical tissue specimens (stomach), and performed an immunohistochemical analysis to evaluate the inflammatory infiltration of the TME. Patients receiving OI were compared with patients receiving standard oral nutritional supplements and no nutritional support. Results: We enrolled 12 patients with gastric cancer in the study. The median body weight loss was 5.6%. Four patients received OI, five patients received standard nutritional supplement, and three patients received no nutritional supplementation. No difference in age, body mass index (BMI), and body weight loss was observed between the three groups. The OI group showed a tendency of increased number of T-lymphocyte cluster of differentiation (CD) 8+ compared with the other groups, as well as the number of CD83+ and CD68+. The absence of F4/80+ cells was documented only in the TME of the OI group, where a linear positive correlation was present between lymphocytes CD4+ and CD8+ (R = 0.48), and between CD4+ and CD83+ (R = 0.89), although not statistically significant. In the OI group, we observed a positive correlation (not significant) between the number of lymphocytes CD8+ and macrophages CD68+ (R = 0.70; P = 0.30). A strong significant correlation was documented between CD68+ and CD40+ (R = 0.99; P = 0.01), but this correlation did not reach the significance among the patients of the other two groups (R = 0.60; P = 0.116). Conclusions: The administration of OI in patients with gastric cancer might determine changes in inflammatory patterns of the TME.